Finding the Fourth Proportional to 12,143.20, 18,200.18 and 5,120.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12,143.20 : 18,200.18 = 5,120.50 : x
2. Step 2: Convert to fraction form
   12,143.20/18,200.18 = 5,120.50/x
3. Step 3: Cross multiply
   12,143.20x = 18,200.18 × 5,120.50
4. Step 4: Simplify right side
   12,143.20x = 93,194,021.69
5. Step 5: Solve for x
   x = 93,194,021.69/12,143.20
6. Step 6: Final answer
   x = 7,674.59